CHM1020 Exam 2

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In the compound MgO, the Mg ion has a charge of _____, while the O ion has a charge of _____

+2, -2

What, approximately, is the highest concentration of CO2 measured in the Earth's atmosphere in modern times?

400ppm

A substance that participates in a chemical reaction but is regenerated so that it undergoes no permanent change is called a(n)

catalyst

Match each element with the appropriate charge in its ionic form. 1. Cl 2. Sr 3. S 4. Al

1. -1 2. +2 3. -2 4. +3

how many valence electrons do the following elements have? 1. C 2. Be 3. Ne 4. F

1. 4 2. 2 3. 8 4. 7

How many lone pairs would an oxygen atom have (a single O atom)?

2

A boron (B) atom has _____ valence electrons

3

Dobson unit is equivalent to ______ O3 molecules in a vertical column of air with cross-section of 1 cm2

3 × 10^16

What is meant by the term "carbon footprint" when applied to an individual?

An estimate of the amount of CO2 and other greenhouse gas emissions produced by the individual in a given time frame

cation

An ion with fewer electrons than its neutral atom is called a(n)

anion

An ion with more electrons than its neutral atom is called a(n)

Which color in the rainbow has the shortest wavelength?

Blue

Which human activity has the GREATEST net effect on atmospheric CO2 levels?

Burning fossil fuels

Which of the following human activities increase the levels of atmospheric CO2?

Burning fossil fuels Replacing trees with cultivated crops Respiration

The most significant step toward halting the depletion of the ozone layer was the call to stop the production of

CFCs

Which of the following options correctly describe variations in solar irradiance and its effect on Earth's climate?

Changes in the Earth's orbit can affect the amount of solar radiation that reaches the Earth. Seasonal variations in sunlight intensity affect local temperatures significantly.

CFCs always contain

Chlorine, carbon, and fluorine

The most electronegative element is

Fluorine

Which of these represents the best Lewis structure for acetylene (C2H2)?

H-C=-C-H

The most abundant greenhouse gas in Earth's atmosphere is

H2O water vapor

Which of the following statements correctly describe ions?

Ions are formed when atoms lose or gain electrons. F- is an example of an anion.

What is the effect of the absorption of infrared energy on matter?

It increases the vibration of chemical bonds

Which of the following has the greatest impact on global warming?

Levels of atmospheric greenhouse gases

Which atmospheric component does not contribute to global warming?

N2

Select the allotrope of oxygen whose bonds can be broken by UVB radiation

O3

Which of the following can be attributed to the atmosphere of planet Earth?

The Earth's average temperature is higher than expected when considering its distance from the Sun.

An ecological footprint estimates the biologically productive space required to support a particular lifestyle. Which of the following are included in this estimate? Select all that apply.

Sea surface Fresh water Land

What was the role of the IPCC (International Panel on Climate Change), established in 1988?

The IPCC was to assess both scientific and socioeconomic data relating to climate change.

How do mineral nanoparticles in sunscreens protect from UV radiation?

The particles absorb incoming UV light

Which of the following statements correctly describes the consequences of halting the production of CFCs?

There has been a slow decrease in the concentration of stratospheric chlorine since the halt in production of CFCs.

which of the following is true about CFCs

They are chemically persistent molecules, and are inert and nontoxic

frequency symbol

V

A single covalent bond is indicated by

a single solid line

The lewis structure for N2 has

a triple bond, two lone pairs

For an electron to jump from a lower level to a higher one, it must ________ energy

absorb

The proportion of incoming radiation that is reflected by a surface is called the ________. This quantity is a measure of the reflectivity of a surface.

albedo

ionic bond matches

attraction between oppositely charged ions

An estimate of the biologically productive space necessary to support a particular standard of living is called a(n)

ecological footprint

A highly reactive species with one or more unpaired electrons is called a(n)

free radical

For the main-group elements (1, 2, etc.) the number of valence electrons for an element is equal to the ______ number for the element

group

Introducing too many Cl atoms into a potential replacement for CFCs causes a(n) _____ in flammability and a(n) _____ in boiling point.

increase, increase

In chemistry, the mole _______.

indicates amount of substance is abbreviated mol

In a(n) _____ compound electrons are transferred from one atom or group of atoms to another. Conversely, in a(n) _____ compound electrons are shared.

ionic, covalent

The speed of light in air

is independent of the wavelength and frequency of light.

As the wavelength of light decreases (gets shorter) what happens to the frequency of that light, assuming the speed of light stays the same?

it increases

The molar mass of any substance is the mass of 1 _______ of the particles of that substance

mol

During the Antarctic spring, ozone is destroyed at a greater rate than it is formed

on the surface of atmospheric ice crystals. in a process that is catalytic. in polar stratospheric clouds.

When only one pair of shared electrons is involved in a covalent bond, the linkage is called a __________ bond.

single

What shape would a molecule of carbon tetrachloride have?

tetrahedral

Calculate the wavelength of a wave with velocity of 5.1 x 104 m/s and frequency of 1.1 x 108 s-1.

4.6 x 10^ 4

steps for drawing a Lewis structure in the correct order, starting with the first step at the top of the list.

1. Count the number of outer electrons contributed by each atom 2. Add the valence electrons contributed by each individual atoms to determine the total number of outer electrons for the species 3. Arrange the outer electrons in pairs around the contributing atoms 4. Ensure that each atoms has a full outer shell

Rank the three types of UV radiation in order of increasing wavelength, starting with the shortest wavelength radiation at the top of the list.

UVC< UVB< UVA

When naming an ionic compound, the _____ is always named first. To name the anion, the root of the nonmetal name is added to the suffix _____.

cation; -ide

Which of the following statements correctly describe a photon?

matter cannot absorb or emit a fraction of a photon, a photon is a particle of electromagnetic radiation

mass ratio of H, mass percent of H

0.176, 17.6

mass ratio of N, mass percent of N

0.824, 82.4

Which of the following options correctly interpret the information provided by the balanced equation CH4 + 2O2 → CO2 + 2H2O?

1 molecule of CH4 reacts with 2 molecules of O2. 1 mole of CH4 produces 1 mole of CO2 when reacted with 2 moles of O2. 15 mol of CH4 will produce 15 mol of CO2 when burned completely in O2.

Place the reaction steps in order for the reaction of a CFC molecule with stratospheric ozone, starting with the first step at the top of the list

1. A CFC molecule is bombarded with UV light releasing a chlorine radical 2. Chlorine radicals react with ozone to produce ClO and Oxygen 3. ClOO decomposes to a chlorine radical and oxygen

Correctly order the steps required to determine the shape of a molecule, starting with the first step at the top of the list.

1. determine the number of outer electrons associated with each atoms in the molecule 2. arrange the outer electrons in pairs, ensuring that all atoms other than hydrogen obey the octet rule 3. determine the shape of the molecular by examining the position of the bonding and non bonding electron pairs with respect to each other

A mole of CO2 contains how many oxygen atoms?

1.20 x 10^24

Calculate the velocity of a wave with a frequency of 3.5 x 10-5 s-1 and wavelength of 5.1 x 108 m

1.8 x 10^4

To draw a Lewis structure, first add the number of outer (valence) electrons contributed by each atom to obtain the total number of outer electrons. What is this value for a molecule of C2H2?

10 outer electrons

Sunspots typically occur about every

11 years

What is the molar mass of dimethylglyoxime, C4H8N2O2?

116.12 g/mol

The history of average global temperature for the last 160,000 years is derived from isotopic analysis of ice layers in Antarctica. Scientists study the ________ ratio in ________.

1H/2H; H2O

In a vacuum all electromagnetic radiation travels at a constant speed:

3.00x10^8

WUKF FM transmits at 93.5 MHz. What is the wavelength of the electromagnetic radiation that carries the station's signal?

3.21 m

How much energy (in joules) would a photon of green light (wavelength 532 nm) have?

3.74 x 10^ -19

To draw a Lewis structure, first add the number of outer (valence) electrons contributed by each atom to obtain the total number of outer electrons. What is this value for a molecule of CF2Cl2?

32 total valence electrons

Calculate the mass of 2.50 × 104 molecules of nitrogen gas.

5.81 × 10^¯19 g

Give the number of outer (valence) electrons for an atom of bromine.

7

The octet rule states that when atoms bond they may lose, gain, or share electrons in order to attain an outer level containing __________ electrons

8

Atoms bond in order to fill their valence shell of electrons. Most elements strive for a total of _____ such electrons while hydrogen strives for a total of _____.

8, 2

Which of the following statements correctly describe the general characteristics of a covalent bond

A covalent bond involves the attraction between the nucleus of each atom and the electrons of the other, A covalent bond involves the sharing of electrons between two atoms, Electrons in a covalent bond are common property to both atoms that make up the bond

Which of the following greenhouse gases would require a wedge and dash representation in order to accurately depict its shape?

CCl2F2

During photosynthesis ________.

CO2 and H2O are consumed to produce stored glucose, sunlight is converted into stored chemical potential energy

Although carbon dioxide is the primary compound discussed with respect to global warming; of the common atmospheric components the global warming potential (GWP) of a carbon dioxide molecule is very low. Which statement best explains this pair of facts?

CO2 exists in relatively high concentrations

Which of the following elements will form a cation?

Ca and Rb (because they are both metals)

Which of the following ion combinations will result in an ionic compound that has a balanced number of positive and negative charges?

Ca2+ and 2 F -, 2 Li+ and S2-, Na+ and Br -

Which of the following formulas for ionic compounds are correct?

CaO Ca3N2

Which of the following radicals are responsible for ozone depletion by CFCs

ClO, Cl

Which statements describe an ionic compound?

Compounds that contain no molecules. Compounds formed when metals combine with nonmetals.

In the compound CrCl3 _______

Cr has a +3 charge Cl has a -1 charge

Replacing halogen atoms (such as Cl) in CFCs with hydrogen results in a(n) _

Decrease in boiling point and decrease in molar mass

The ______ unit is a means of measuring ozone concentration, which is based on the intensity of UV radiation through a column of air.

Dobson

Which of the following options correctly describes the underlying principle used to determine molecular shape from a Lewis structure?

Each group of outer electrons around a central atom is located as far from the others as possible.

Which of the following options correctly describe how to draw a Lewis structure for a given molecule?

Each line between two atoms represents two electrons, The Lewis structure includes only the valence electrons for the molecule, The A-group number of a main-group element gives the number of valence electrons

True or false: Once the production of CFCs was halted there was a dramatic decrease in the amount of stratospheric chlorine.

False

Where is most of the carbon on earth stored?

In the form of fossil fuels and carbonate minerals and rocks

Which of the following statements correctly describe a Lewis structure?

Lone pairs are shown as pairs of dots on individual atoms, Bonding electrons are shown as lines or pairs of dots between two atoms

Which of the following options correctly describe each type of chemical compound?

Molecular compounds tend to contain nonmetals only, Nonmetals combine with metals to form ionic compounds.

Which of the following are three-dimensional representations of a molecule? Select all that apply.

Space-filling model Wedge-dash representation

Which of the following options correctly describe the UV Index?

The UV Index is based on the length of time required for skin damage to occur, A UV Index color-coded yellow indicates a moderate level of UV radiation

Which of the following options correctly describe albedo? Select all that apply.

The albedo of the Earth affects global temperatures. Albedo is the fraction of incoming radiation that is reflected by a surface. A more reflective surface will have a higher albedo than a less reflective one.

Which of the following conclusions were reached by the IPCC (International Panel on Climate Change)?

The average global temperature of the Earth is increasing. The burning of fossil fuels has a major impact on climate change. Human activities play an important role in climate change.

Which of the following options correctly describe how to name an ionic compound?

The cation is named first and the anion second, When naming the anionic portion of the ionic compound, the element name is changed to end in -ide.

Which of the following options correctly describe the greenhouse effect?

The greenhouse effect is a natural process. Atmospheric gases on Earth trap about 80% of the infrared radiation produced by the Earth, warming the planet. The greenhouse effect causes the average temperature on Earth to be higher than predicted when considering its distance from the Sun.

Select the options that correctly reflect the mass ratios and mass percentages of the elements in SO3.

The mass ratio of S is 0.400. The mass percentage of O is 60.0%.

Which statement correctly describes the procedure used to predict the ion formed by Group 1 and Group 2 elements (part of the main groups elements) ?

The metal loses enough electrons to attain the same number as its nearest noble gas.

Which of the following statements correctly describe molar mass?

The molar mass of oxygen is 16.00 g/mol. This means that 1 mole of oxygen atoms has a mass of 16.00 g. The periodic table can be used to calculate the molar mass of any substance. The molar mass of a molecular substance is the mass per mole of its molecules.

Which of the following statements correctly describe the mole?

The number of particles in a mole is called Avogadro's number. One mole of any substance contains 6.02 x 10^23 particles.

Which conclusion was considered "very likely" in the 2014 report of the Intergovernmental Panel on Climate Change?

The observed warming of the past 100 years is due solely to climate variability

Which of the following options correctly describe the steps required to determine the shape of a molecule? Select all that apply.

The shape of the molecule is dictated by the most stable arrangement of the outer electron pairs. The Lewis structure of the molecule must be drawn first. Both bonding and nonbonding electron pairs must be considered.

Which of the following options correctly differentiate between weather and climate? Select all that apply.

The term "climate" refers to regional trends in temperatures, rainfall, etc. Weather includes daily variations in temperature and rainfall at a single location. The term "weather" refers to events that have a relatively short duration.

H2O2 (connectivity is HOOH)

This molecule possesses no multiple bonds

HCN

This molecule possesses one triple bond

CS2

This molecule possesses two double bonds

Which of the following is a common ingredient in mineral-based sunblock formulations?

TiO2 or ZnO

T/F: CFCs are inert, nontoxic compounds

True

Which of the following options correctly describe the different types of UV radiation? Select all that apply.

UV radiation with a wavelength of 300 nm is classified as UV-B radiation, UV-A is the least damaging to the Earth's surface, UV-C radiation has the shortest wavelength

Which of the following regions of the electromagnetic spectrum have sufficient energy to break covalent bonds?

UV, X-ray

Consider the Bohr model of an atom, in which electrons reside in energy levels, denoted as n, starting from nearby the nucleus (n = 1) to farther away from the nucleus (n = 3). Which of the following electronic transitions would result in the emission of light with the shortest wavelength?

an electron moving from the n= 3 level to n= 1

covalent bond

attraction between two nuclei and a shared pair of electrons

Both Venus and Earth have higher average surface temperatures than expected because _____.

both planets have atmospheres that trap radiation

Which atom in a molecule of CH3Cl would contain the partial negative charge? (this relates to electronegativity)

chlorine

Any bond that involves the sharing of two electrons is known as a(n) ________ bond.

covalent

The bond formed between two nonmetals is called a(n) _____ bond. This bond involves the _____ of one or more electron pairs between the two atoms

covalent; sharing

Lewis structures are used to represent covalent compounds. Shared electron pairs are shown either as pairs of ________ or lines and only _______ electrons are shown

dots, valence or outer

In the formation of ionic compounds a nonmetal will ______ electrons to form an ion with the same number of electrons as the nearest ______ gas.

gain; noble

Greenhouse gases have a _____ effect on global warming than other anthropogenic forcings

greater

Wavelength and frequency are _____ proportional to each other. As wavelength increases frequency will _____.

inversely, decrease

In the formation of ionic compounds a metal will ______ electrons and a nonmetal will ______ electrons to form an ion with the same number of electrons as the nearest ______ gas.

lose; gain; noble

one _________ of any substance contain Avogardo's number of particles

mol

Chemists use the _____ as a unit of amount of substance.

mole

In general ozone (O3) is much _____ reactive than oxygen (O2)

more

The charge of an ion with more electrons than its neutral atom is

negative

Consider the balanced equation 2H2 + O2 → 2H2O. The coefficients (numbers in front of the formulas) correspond to the number of particles of each substance involved in the reaction, which is proportional to the _____ of each substance

number of moles

The chemistry of carbon-based compounds is called ______ chemistry.

organic

frequency is usually measured as the distance between two _________ or two troughs

peaks/ crests

Which of the following can cause electrons in a ground state to go to a higher level excited state?

photon absorption

Electromagnetic radiation consists of particles called ______________, each of which has a discrete amount, or quantum, or energy, However, since electromagnetic radiation also has wave properties, each particle is also characterized by a specific ____________ and frequency

photons, wavelengths/ energy

The process by which green plants convert sunlight into stored chemical potential energy by producing glucose and oxygen is called

photosynthesis

The charge of an ion with fewer electrons than its neutral atom is

positive

structural formula

representation of how atoms are arragned, omitting lone pairs of electrons

Lewis structure

representation of how atoms are connected, including lone pairs of electrons

The pair of electrons involved in a covalent bond is called a(n) _____ electron pair, whereas the electrons not involved in bonding are called an unshared or ______ pair

shared/bonding, lone

Chemical formula

shows only types and ratios of atoms present

Draw the Lewis structure for the covalent molecule CCl4. Which of the following statements correctly describes the Lewis structure of CCl4?

the Lewis structure of CCl4 contains 12 lone pairs, the Lewis structure of CCl4 contains four single bonds

frequency

the number if wave cycles per second

Organic chemistry is __

the study and production of carbon-containing compounds

Lewis structure for N2

triple bond, two lone pairs

Which of the following is the correct Lewis structure for the molecule OF2?

two bonds, 8 lone pairs

DNA, the genetic material of living organisms, is damaged by light in the

ultraviolet region, especially below a wavelength of 320 nm.

Electronegativity generally increases _______ on the periodic table, excluding noble gases.

up and to the right

Electrons that are found in the highest energy level are called

valence electrons

The most stable molecular arrangement is the one in which the ___________electron groups are as far apart as possible, to minimize electron-electron___________

valence, interaction

When a molecule absorbs an infrared photon it contributes to the ________energy of that molecule.

vibrational

wavelenght formula

wave velocity/ frequency

the distance a wave treavels during one cycle

wavelength

equation for velocity (speed) of a wave

wavelength x frequency

wavelength symbol

λ or nm


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